Generally, the headrest for cars, provided on the upper part of the seat back, is used for the occupant of the seat to rest the head on it by adjusting its height up and down and its position forward and backward and protect the neck and head from being injured by preventing them from the abrupt backward movement due to a car accident, particularly a rear-end collision.
There has been a need for foldable headrests, because the upright type headrests can obstruct the driver's view when looking rearward and the view of the rear seat occupants as well.
The U.S. Pat. No. 6,302,485 discloses a foldable headrest device for giving a wide rear field of view to the driver or a passenger seated in the front seat and the headrest device 4 includes a headrest body 1 supported on a frame 3 of the seat back 2 of the vehicles rear seat by virtue of a stay member 5 (see FIG. 1). The headrest body, rotatably supported on horizontal shaft portion 6 of the stay member, is adapted to be selectively moved between two positions, an upright position (i.e., a used position) and a folded position (i.e., a non-used position) and positioned at one of the two positions, as can be seen from FIG. 1.
As shown in FIG. 2, the headrest device 4 comprises a stopper element 8 having a pair of downwardly extending leg portions 9, 10 at the lower portion and laterally stepped stopper portions 11, 12 at the upper portion and secured on the central portion of the horizontal shaft portion 6 of the stay member, a rotating element 14 rotatably supported on the horizontal portion 6 of the stay member through a pair of brackets 15 that are arranged on opposite sides of the stopper element, an operating lever 16 having a locking mechanism in the form of a pair of downwardly extending and separately provided spaced apart locking elements 17, 18, a pair of elongated holes 19, 20 with pins 22 and 23 disposed therethrough and an operating portion 21 and always biased by the force of the spring 24, and an approximately U-shaped torsion bar 25 with the horizontal portion 26 in contact with the front and rear surfaces of the pair of leg portions of the stopper element, a shorter leg portion 27 engaging the spring hanging portion 13 of the stopper element and a longer leg portion 28 slidably supported on the rotating element and applying its spring force to the headrest body to make the rotating element folded to the housed position. The headrest body as described above has a disadvantage of complicated structures of the stopper element, the rotating element and the operating element as well as the complexity of assembling them on the stay member, making the manufacturing and assembling thereof very difficult and troublesome.
The above problems lead to poor productivity and quality of the device, while the largeness of the elements resulted in waste of materials, increasing the manufacturing costs as well as the size and weight of the device.